Tire layer (3)
I believe the answer is:
ply
'tire layer' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ply that I've seen before include "Use or wield, tool or weapon" , "Laminate thickness" , "Work steadily as at one's trade" , "This wood is laminated" , "Practise (a trade)" .)